Different studies suggest that high intake of nutrient minerals such as Calcium, Phosphorus and Copper; and deficient levels of minerals such as Magnesium, Zinc and Selenium, are associated with increased risk of cancer. We should take foods/nutrition high in Zinc, Magnesium and Selenium in the right quantities and also limit the intake of nutrient minerals such as Calcium, Phosphorus and Copper to the recommended amounts to reduce the risk of cancer. While choosing supplements, one should not confuse magnesium stearate for magnesium supplements. A balanced healthy diet of natural foods is the right approach for maintaining the recommended levels of the essential mineral nutrients in our body and reduce the risk of diseases including cancer.
There are many minerals we intake with our diet and nutrition that are essential for our basic bodily functions. There are minerals that are part of macro requirements such as Calcium (Ca), Magnesium (Mg), Sodium (Na), Potassium (K), Phosphorus (P), that are needed in substantial amounts for our health. There are minerals obtained from foods/nutrition that are needed in trace amounts as part of micro requirement and include substances such as Zinc (Zn), Iron (Fe), Selenium (Se), Iodine (I), Copper (Cu), Manganese (Mn), Chromium (Cr) and others. Most of our mineral nutrition is obtained from eating a healthy and balanced diet. However, due to various reasons of unhealthy lifestyle and diet, poverty and lack of affordability, there is a widespread imbalance in availability of these essential mineral nutrients with either deficiency or excesses that in turn have a negative impact on our health. Besides the key functions of these minerals for different physiological functions, we are going to specifically examine the literature on the impact of excess or deficient levels of some of these key minerals in relation to cancer risk.
Nutrient Mineral – Calcium (Ca):
Calcium, one of the most abundant minerals in the body, is essential for building strong bones, teeth and for muscle function. A trace amount of Calcium is also needed for other functions such as vascular contractions, nerve transmission, intracellular signaling and hormone secretion.
Recommended daily allowance for Calcium varies with age but is in the range of 1000-1200 mg for adults between ages of 19 to 70 years.
Calcium-rich food sources: Dairy foods including milk, cheese, yogurt are rich natural sources of Calcium. Plant based foods rich in Calcium include vegetables such as Chinese cabbage, kale, broccoli. Spinach also contains Calcium but it’s bioavailability is poor.
Calcium intake and Cancer risk: Several earlier studies had found that higher intake of the mineral Calcium from foods (low-fat dairy sources) or supplements are associated with a decreased risk of colon cancer. (Slattery M et al, Am J Epidemiology, 1999; Kampman E et al, Cancer causes control, 2000; Biasco G and Paganelli M, Ann N Y Acad Sci, 1999) In a Calcium Polyp Prevention study, supplementation with Calcium carbonate led to reduction in developing the pre-cancerous, non-malignant, adenoma tumors in the colon. (Grau MV et al, J Natl Cancer Inst., 2007)
However, a more recent observational study on 1169 newly diagnosed colorectal cancer patients (stage I – III) has not shown any protective association or benefits of Calcium intake and all-cause mortality. (Wesselink E et al, The Am J of Clin Nutrition, 2020) There are multiple such studies that have found inconclusive associations of Calcium intake and decreased colorectal cancer risk. Hence there is not enough evidence to recommend the routine use of Calcium supplements to prevent colorectal cancer.
On the other hand, another recent study linked to the National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2010 on a very large cohort of 30,899 US adults, 20 years or older, found that excess intake of Calcium was associated with increased cancer deaths. The association seemed to be related to excess intake of Calcium greater than 1000 mg/day vs. no supplementation. (Chen F et al, Annals of Int Med., 2019)
There are several studies that have found an association between high intakes of Calcium greater than 1500 mg/day and an increased risk of developing prostate cancer. (Chan JM et al, Am J of Clin Nutr., 2001; Rodriguez C et al, Cancer Epidemiol Biomarkers Prev., 2003; Mitrou PN et al, Int J Cancer, 2007)
Key take-away: We do need to have adequate intake of Calcium for our bone and muscle health, but excessive Calcium supplementation beyond the recommended daily allowance of 1000-1200 mg/day may not be necessarily helpful, and may have a negative association with increased cancer related mortality. Calcium from natural food sources as part of a balanced healthy diet is recommended over using high dose Calcium supplements.
Nutrient Mineral – Magnesium (Mg):
Magnesium, besides its role in bone and muscle functioning, is a key cofactor for a large number of enzymes involved in diverse biochemical reactions in the body. Magnesium is required for metabolism, energy production, synthesis of DNA, RNA, proteins and antioxidants, muscle and nerve function, blood glucose control and blood pressure regulation.
Recommended daily allowance for Magnesium varies with age but is in the range of 400-420 mg for adult males, and about 310-320 mg for adult females, between ages of 19 to 51 years.
Magnesium-rich food sources: Include green leafy vegetables such as spinach, legumes, nuts, seeds and whole grains, and foods containing dietary fiber. Fish, dairy products and lean meats are also good sources of Magnesium.
Magnesium intake and cancer risk: The association of dietary intake and risk of colorectal cancer has been examined by many prospective studies but with inconsistent findings. A meta-analysis of 7 prospective cohort studies was conducted and found a statistically significant association of reduction in risk of colorectal cancer with Magnesium mineral intake in the range of 200-270mg/day. (Qu X et al, Eur J Gastroenterol Hepatol, 2013; Chen GC et al, Eur J Clin Nutr., 2012) Another recent study also found a decreased all-cause mortality risk in colorectal cancer patients with a higher intake of Magnesium along with adequate levels of Vitamin D3 when compared to patients who were Vitamin D3 deficient and had a low intake of Magnesium. (Wesselink E, The Am J of Clin Nutr., 2020) Another study that looked at prospective association of serum and dietary Magnesium with colorectal cancer incidence, found a higher risk of colorectal cancer with lower serum Magnesium among females, but not males. (Polter EJ et al, Cancer Epidemiol Biomarkers Prev, 2019)
Another large prospective study investigated the association of Magnesium intake and risk of pancreatic cancer in 66,806 men and women, aged 50-76 years. The study found that every 100 mg/day decrease in Magnesium intake was associated with a 24% increase in pancreatic cancer. Therefore, adequate Magnesium intake may be beneficial for reducing risk of pancreatic cancer. (Dibaba D et al, Br J Cancer, 2015)
Key take-away: Eating Magnesium-rich foods as part of a healthy, balanced diet is essential for obtaining the recommended levels of Magnesium in our bodies. If required, it can be supplemented with Magnesium supplements. Clinical studies do indicate that low Magnesium levels are associated with a higher risk of colorectal and pancreatic cancers. While Magnesium intake from foods is beneficial, excessive Magnesium supplementation beyond the required levels can be harmful.
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What is Magnesium Stearate? Is it a supplement?
One should not confuse Magnesium stearate with Magnesium supplement. Magnesium stearate is a widely used food additive. Magnesium stearate is the magnesium salt of a fatty acid called stearic acid. It is widely used in the food industry as a flow agent, an emulsifier, binder and thickener, lubricant and antifoaming agent.
Magnesium stearate is used in the production of dietary supplements and medication tablets, capsules and powders. It is also used in many food products such as confectionery, spices and baking ingredients and also in cosmetics. When ingested, magnesium stearate breaks into its component ions, magnesium and stearic and palmitic acids. Magnesium stearate has a GRAS (Generally Recognized as Safe) status in the United States and in most of the world. Intake of Magnesium stearate, up to 2.5g per kg per day is considered to be safe. Excessive intake of Magnesium stearate may lead to bowel disorders and even diarrhea. If taken under recommended doses, Magnesium stearate may not lead to undesired effects.
Nutrient Mineral – Phosphorus/Phosphate (Pi):
Phosphorus an essential mineral nutrient is part of many foods, mainly in the form of phosphates (Pi). It is a component of bones, teeth, DNA, RNA, cell membranes in the form of phospholipids and the energy source ATP (adenosine triphosphate). Many enzymes and biomolecules in our body are phosphorylated.
Recommended daily allowance for Phosphorus is in the range of 700-1000 mg for adults greater than 19 years of age. It is estimated that Americans intake almost twice the recommended amounts due to a higher consumption of processed foods.
Phosphate-rich food sources: It is naturally present in raw foods including vegetables, meats, fish, eggs, dairy products; Phosphate is also found as an additive in a large number of processed foods including burgers, pizza and even soda beverages. Addition of Phosphate helps with increasing quality of processed foods, but is not listed as an ingredient per se. Therefore, foods with Phosphate additives not only have 70% higher Phosphate content than raw foods and contribute to 10-50% of phosphorus intake in Western countries. (NIH.gov factsheet)
Phosphorus intake and cancer risk: In a 24 year follow-up study in 47,885 men based on analysis of reported diet data, it was found that high phosphorus intake was associated with increased risk of advanced stage and high-grade prostate cancer. (Wilson KM et al, Am J Clin Nutr., 2015)
Another large population study in Sweden found a higher overall cancer risk with increasing levels of Phosphates. In men, the risk of cancer of the pancreas, lung, thyroid gland and bone was higher while in women, there was increased risk associated with cancer of the oesophagus, lung and nonmelanoma skin cancers. (Wulaningsih W et al, BMC Cancer, 2013)
An experimental study showed that compared to mice that were fed a normal diet, mice fed a diet high in Phosphates had increased lung tumor progression and growth, thus linking high Phosphate to a higher risk of lung cancer. (Jin H et al, Am J of Respiratory and Critical Care Med., 2008)
Key take-away: The nutritional advice and recommendations on eating more natural foods and vegetables and lower quantities of processed foods helps in keeping the levels of Phosphate in the required healthy range. Abnormal Phosphate levels are related to increased risk of cancer.
Nutrient Mineral – Zinc (Zn):
Zinc is an essential mineral nutrient naturally present in some foods and involved in numerous aspects of cellular metabolism. It is required for the catalytic activity of many enzymes. It plays a role in immune function, protein synthesis, DNA synthesis and repair, wound healing and cell division. The body has no specialized Zinc storage system, hence has to be replenished through a daily intake of Zinc via foods.
Recommended daily allowance for Zinc through intake of foods / supplements is in the range of 8-12mg for adults greater than 19 years of age. (NIH.gov factsheet) Zinc deficiency is a global health problem affecting over 2 billion people worldwide. (Wessells KR et al, PLoS One, 2012; Brown KH et al, Food Nutr. Bull., 2010) Taking Zinc rich foods in the right quantities hence becomes crucial.
Zinc-rich food sources: A wide variety of foods contain Zinc, including beans, nuts, certain types of seafood (such as crab, lobster, oyster), red meat, poultry, whole grains, fortified breakfast cereals, and dairy products.
Zinc intake and cancer risk: The anti cancer effects of Zn are mostly associated with its anti-oxidant and anti-inflammatory properties. (Wessels I et al, Nutrients, 2017; Skrajnowska D et al, Nutrients, 2019) There are numerous studies that have reported the association of Zinc deficiency(due to low intake of Zinc rich foods) with increased risk of cancer, as listed below:
- A case controlled study part of the European Prospective Investigation into Cancer and Nutrition cohort found an association of increased Zinc mineral levels with decreased risk of liver cancer (hepatocellular carcinoma) development. They found no association of Zinc levels with bile duct and gall bladder cancers. (Stepien M wt al, Br J Cancer, 2017)
- There was a significant decrease in serum Zinc levels found in newly diagnosed breast cancer patients when compared to healthy volunteers. (Kumar R et al, J Cancer Res. Ther., 2017)
- In an Iranian cohort, they found a significant decreased level of serum Zinc in colorectal cancer patients compared to healthy controls. (Khoshdel Z et al, Biol. Trace Elem. Res., 2015)
- A meta analysis reported significantly lower serum Zinc levels in lung cancer patients with healthy controls. (Wang Y et al, World J Surg. Oncol., 2019)
Similar trends of low Zinc levels have been reported in many other cancers as well including head and neck, cervical, thyroid, prostate and others.
Key take-away: Maintaining the required levels of Zinc through our dietary/food consumption and if required additional supplementation is essential for supporting a robust immune and antioxidant defense system in our body, that is key for cancer prevention. There is no Zinc storage system in our bodies. Therefore Zinc has to be obtained through our diets/foods. Excessive Zinc supplementation beyond the required levels can have negative effects through suppressing the immune system. Taking required amounts of Zn via intake of Zinc rich foods instead of high intake of supplements may be beneficial.
Selenium Nutrition (Se):
Selenium is a trace element essential in human nutrition. It plays a major role in protecting the body against oxidative damage and infections. Additionally, it also plays critical roles in reproduction, thyroid hormone metabolism and DNA synthesis.
Recommended daily allowance for Selenium via nutrition is 55mcg for adults greater than 19 years of age. (NIH.gov factsheet)
Selenium-rich food/nutrition sources: The amount of Selenium found in natural food/nutrition is dependent on the amount of Selenium present in the soil at the time of growth, so it varies in different foods from different regions. However, one is able to fulfill Selenium nutrition requirements through eating brazil nuts, breads, brewers yeast, garlic, onions, grains, meat, poultry, fish, eggs and dairy products.
Selenium nutrition and cancer risk: Low Selenium levels in the body have been associated with increased risk of mortality and poor immune function. Many studies have shown the benefits of higher Selenium mineral status on the risk of prostate, lung, colorectal and bladder cancers. (Rayman MP, Lancet, 2012)
Selenium Supplements of 200mcg/day reduced prostate cancer incidence by 50%, lung cancer incidence by 30%, and colorectal cancer incidence by 54%. (Reid ME et al, Nutr & Cancer, 2008) For healthy people not diagnosed with cancer, including Selenium as part of nutrition was reported to strengthen their immunity by increasing the activity of natural killer cells. (Büntzel J et al, Anticancer Res., 2010)
Additionally nutrition rich in Selenium also helps cancer patients by reducing toxicities related to chemotherapy. These supplements were shown to significantly lower infection rates for Non-Hodgkin’s Lymphoma patients. (Asfour IA et al, Biol. Trace Elm. Res., 2006) Selenium nutrition has also been shown to decrease certain chemo induced kidney toxicity and bone marrow suppression (Hu YJ et al, Biol. Trace Elem. Res., 1997), and reduce radiation induced toxicity of a difficulty in swallowing. (Büntzel J et al, Anticancer Res., 2010)
Key take-away: All anti-cancer benefits of Selenium may only apply if Selenium levels in the individual are already low. Selenium supplementation in individuals who already have enough Selenium in their body can lead to risk of type 2 diabetes. (Rayman MP, Lancet, 2012) In some cancers such as certain mesothelioma tumors, Selenium supplementation was shown to cause disease progression. (Rose AH et al, Am J Pathol, 2014)
Nutrient Mineral – Copper (Cu):
Copper, an essential trace mineral nutrient, is involved in energy production, iron metabolism, neuropeptide activation, connective tissue synthesis and neurotransmitter synthesis. It is also involved in many physiologic processes including angiogenesis (forming new blood vessels), functioning of the immune system, antioxidant defense, regulation of gene expression and others.
Recommended daily allowance for Copper is 900-1000mcg for adults greater than 19 years of age. (NIH.gov factsheet) We can get our required amount of Copper from our diets.
Copper-rich food sources: Copper can be found in dried beans, almonds, other seeds and nuts, broccoli, garlic, soybeans, peas, wheat bran cereals, whole-grain products, chocolate and seafood.
Copper intake and cancer risk: There are multiple studies that have shown that the Copper concentration in serum and tumor tissue is significantly higher than that of healthy subjects. (Gupta SK et al, J Surg. Oncol., 1991; Wang F et al, Curr Med. Chem, 2010) The higher concentration of Copper mineral in tumor tissues is due to its role in angiogenesis, a key process needed to support the fast growing cancer cells.
A meta analysis of 14 studies reported significant evidence of higher serum copper levels in patients with cervical cancer than in control healthy subjects, supporting the association of higher serum Copper levels as a risk factor for cervical cancer. (Zhang M, Biosci. Rep., 2018)
Another study published in the Proceedings of the National Academy of Sciences in the United States, described the mechanism by which variable levels of Copper in the tumor microenvironment, modulates tumor metabolism and promotes tumor growth. (Ishida S et al, PNAS, 2013)
Key take-away: Copper is an essential element we obtain through our diets. However, excessive levels of Copper mineral due to elevated levels in drinking water or due to a defect in Copper metabolism, can increase the risk of cancer.
The food sources in nature provide us the required amount of mineral nutrients for our health and well being. There can be imbalances due to eating unhealthy, processed food diets, variations in soil content based on geographical locations, variations in levels of minerals in drinking water and other environmental factors that can cause variations in the mineral contents. Excessive level of mineral intake such as Calcium, Phosphorus and Copper; and deficient levels of minerals such as Magnesium, Zinc (low intake of Zinc rich foods) and Selenium, are associated with increased risk of cancer. We should look out for foods high in Zinc, Magnesium and Selenium and take them in the right quantities. One should not confuse magnesium stearate for magnesium supplements. Also, limit the intake of nutrient minerals such as Calcium, Phosphorus and Copper to the recommended amounts to reduce the risk of cancer. A balanced healthy diet of natural foods is the remedy for maintaining the recommended levels of the essential mineral nutrients in our body to stay away from cancer.
“What should I eat?” is the most frequently asked question to cancer dieticians and physicians. The right answer depends upon cancer type, underlying genomics, current treatments, any allergies, lifestyle information, and factors like BMI.
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Cancer patients often have to deal with different chemotherapy side effects which affect their quality of life and look out for alternative therapies for cancer.Taking the right nutrition and supplements based on scientific considerations (avoiding guesswork and random selection) is the best natural remedy for cancer and treatment related side-effects.